White Rock Minerals Ltd. granted Sandfire Resources NL an option to acquire up to a 90% interest in the Red Mountain zinc-silver-lead-gold-copper project in Alaska.

The company can secure an initial 51% by spending A$20 million on exploration over four years, with a minimum A$6 million expenditure in 2019.

It can increase its stake to 70% by spending an additional A$10 million and delivering a pre-feasibility study with an ore reserve within a further two years, according to a March 25 release.

The joint venture will be operated through a U.S.-organized limited liability company, with Sandfire holding a 15% interest and White Rock holding the remaining 85% interest.

If White Rock chooses to not fund its share, Sandfire can take its interest to 80% by sole funding the third expenditure stage, which includes completing a definitive feasibility study.

If White Rock declines contribute to the fourth stage, which includes the start of commercial production, Sandfire can secure an additional 10% interest by sole funding the development.